1. Field of the Invention
The present invention relates to a fan (air blower fan) including an axial flow fan, a centrifugal fan, and so forth.
2. Description of the Related Art
Japanese Patent Application Publication No. 2010-7545 discloses, as an example of a fan, an axial flow fan including an impeller including a plurality of blades, a motor that rotates the impeller, and a housing having an air channel that allows an air to be sucked from the suction port and discharged from the discharge port when the impeller rotates. In the axial flow fan, a surface of the housing, in which the suction port is formed, is a substantially rectangular in profile. For the purpose of reducing noise produced from around the suction port to reduce noise produced from the entire fan, four tapered portions are formed on an end portion of an inner wall surface of the air channel at four locations corresponding to four corners of the profile of the surface of the housing where the suction port is formed, the four tapered portions being each inclined outwardly in the radial direction of a rotary shaft from the discharge port side toward the suction port side and extending in the rotational direction of the impeller.